The international aid agency Oxfam is appealing to European Union foreign ministers to do more to fight Ebola, a disease Oxfam said could be the "definitive humanitarian disaster of our generation."

The chief of the British charity, Mark Goldring, called for more troops, funding and medical staff to be sent to Sierra Leone, Guinea and Liberia, the countries hit hardest by the epidemic. Goldring said countries that fail to make a commitment to fight Ebola "are in danger of costing lives."

Echoing that comment, Liberian President Ellen Johnson Sirleaf said, in an open letter to the BBC Sunday, that the fight against Ebola is one in which "the whole world has a stake."

Sirleaf said, "It is the duty of all, as global citizens, to send a message that they will not leave millions of West Africans to fend for themselves."

She added that the disease was unleashing an economic catastrophe that will leave a “lost generation” of young West Africans.

US quick-reaction team

Meanwhile, a Pentagon spokesman said U.S. Defense Secretary Chuck Hagel has ordered the creation of a 30-member expeditionary medical support team to be able to provide emergency help in the event of an Ebola crisis in the United States.

The plan would be for a team of five doctors, 20 nurses and five trainers to be able to respond on short notice to help civilian medical professionals, a statement from Rear Admiral John Kirby said.

The U.S. will also issue new guidelines for health workers treating Ebola patients that will include using protective gear "with no skin showing.''

The guidelines are expected to set a firmer standard than before, calling for full-body suits and hoods that protect workers' necks, setting rigorous rules for removal of equipment and disinfection of hands, and calling for a "site manager'' to supervise the putting on and taking off of equipment.

Three cases of Ebola have been diagnosed in the United States, prompting widespread concern about the potential spread of the virus. A Liberian man, Thomas Eric Duncan, fell ill while on a trip to Dallas, Texas, and died on October 8.

Two nurses who treated him have contracted the disease. One nurse is being cared for in Bethesda, Maryland, and the other is being treated in Atlanta, Georgia.

Kirby called the team “an added, prudent measure to ensure our nation is ready to respond quickly, effectively and safely in the event of additional Ebola cases. ... They will not be sent to West Africa or elsewhere overseas and will be called upon domestically only if deemed prudent by our public health professionals,” the statement said.

President Barack Obama met with members of his national security and public health teams Saturday evening to discuss the response to the domestic Ebola cases.

21-day monitoring

Some of the dozens of people who are being watched for possible exposure to Ebola in the United States are expected to be cleared on Sunday and Monday, potentially easing concerns about the spread of the disease after two nurses were infected.

At midnight, nearly 50 people who might have been in contact with Duncan will no longer require monitoring for signs of the virus, health officials said Sunday. On Monday, more were expected to end 21 days of monitoring - the incubation period for the virus.

They would include Duncan's fiancee, Louise Troh, her 13-year-old son and two other people who have been in mandatory quarantine at an undisclosed location in Dallas.

Also, a Dallas lab worker who spent much of a Caribbean holiday cruise in isolation tested negative for the deadly virus and left the Carnival Magic liner with other passengers after it docked at Galveston, Texas, early Sunday.

However, there are still 75 health workers in Dallas who have isolated themselves and are being monitored.

The president urged people to keep the situation in perspective. He said the U.S. may see more isolated cases, but said he is "absolutely confident" officials can prevent a serious outbreak.

Texas hospital apologizes

In a public letter on Saturday night, Texas Health Resources Chief Executive Barclay Berdan acknowledged that Texas Health Presbyterian, where Duncan first went, made mistakes, including initially not diagnosing Ebola.

Berdan said aggressive actions since then ensured that the hospital was a safe place, and that outside experts would be consulted to determine how the two nurses became infected.

Canada says it will send 800 vials of an experimental Ebola vaccine to the World Health Organization in Geneva starting Monday. And the U.N. World Food Program delivered emergency rations to more than 260,000 people in the Waterloo district of Freetown, the capital of Sierra Leone.

The area has seen an usually high number of cases of Ebola. Many families have been quarantined.​

The worst outbreak on record of the virus, spread by contact with bodily fluids of sick people, has killed more than 4,500 people, mostly in Liberia, Sierra Leone and Guinea.

FILE - Cuba's former leader Fidel Castro in Havana.

​Cuba would aid US in Ebola fight

Meanwhile, Fidel Castro, the former leader of Cuba, said the Caribbean island nation will "gladly cooperate" with the U.S. in the fight against Ebola in West Africa.

Writing in the state media Saturday, the 88-year-old Castro said the cooperation would be in the interest of "peace in the world," and is not an attempt to resolve issues between the U.S. and Cuba.

"We will gladly cooperate with American personnel in that task and not in search for peace between the two states that have been adversaries for so many years, but in any case, for peace in the world, a goal that can and should be attempted," a Cuban television broadcaster read Castro's remarks on the air.

Secretary of State John Kerry praised Cuba's efforts Friday for its impressive response to the Ebola crisis, saying "Cuba - a country of just 11 million people - has sent 165 health professionals and it plans to send nearly 300 more" to hard-hit West Africa.

Cuba has a history of sending its doctors to emergencies around the world.

"It took our country not one minute to respond to the international agencies before requesting support against the brutal epidemic that has broken out in West Africa. It's what our country has always done without excluding anyone," Castro said in his remarks.

Jorge Perez, director of the tropical disease hospital where Cuban doctors train for the Ebola mission, said he believed the U.S. and Cuban missions to fight Ebola could lead to improved diplomatic relations.

Cuba has sent medical brigades to disaster sites around the world since the 1959 revolution that brought Fidel Castro to power.

Besides medical diplomacy, Cuba sends doctors overseas in exchange for money or goods, notably Venezuelan oil, making professional services a top export earner.

Correction: An early version of this story incorrectly stated the U.N. World Food Program airdropped rations to people in Sierra Leone.The supplies were not airdropped.